Error AFTER uploading Sketch ?

Hi all,

I have just started to get an error after uploading a sketch:

Binary sketch size: 3698 bytes (of a 32256 byte maximum)
avrdude: stk500_getsync(): not in sync: resp=0x00

The top line is in white and is what I normally get after uploading a sketch.
The second line is in Orange and normally is an error line.
Can anybody shed some light on the error, as it's only just started to happen and I'm not sure if I have a problem with my Uno Board?

Thanks all

Double/tripple/quadruple check that you have the correct board type selected?

Did you plug a wire (or anything) into D0 or D1 on the Uno?

Yes I have an LED pluged in and it's not working right, it keeps flashing and it should come on if the something gets closer to the Ultrasonic Range Finder.

Is that the problem?

Plugging something into D0/D1 (Rx/Tx) is going to interfere with sketch uploading. Perhaps choose a different pin for your LED. And make sure you have a resistor in series with it.